c# - 检查集合是否为空

Question

public ActionResult Create(FormCollection collection, FormCollection formValue)
{
    try
    {
        Project project = new Project();

        TryUpdateModel(project, _updateableFields);

        var devices = collection["devices"];
        string[] arr1 = ((string)devices).Split(',');
        int[] arr2 = Array.ConvertAll(arr1, s => int.Parse(s));

        project.User = SessionVariables.AuthenticatedUser;
        var time = formValue["Date"];
        project.Date = time;
        project.SaveAndFlush();

        foreach (int i in arr2)
        {
            Device d = Device.Find(i);
            d.Projects.Add(project);
            d.SaveAndFlush();
        }

        return RedirectToAction("Index");
    }
    catch (Exception e)
    {
        return View(e);
    }
}

我想将 foreach 包装在一个 if 语句中以检查是否

var devices = collection["devices"];

是否为空。如果它为空，则不应执行 for each。郑重声明，collection["devices"] 是表单中复选框值的集合。

Answer 1

您可以使用Count 字段来检查集合是否为空

所以你最终会得到这样的结果:

if(devices.Count > 0)
{
   //foreach loop
}